I am a worry wart, when it comes to being ready for the one shot that I may have on a trophy. Therefore, I go back to the range many times, even after settling on a formula for my game load. Going back again and again is not a bad thing, but on an off day, when I am not grouping well at 200 yards, I simply move the target in to 100 yards and get a good group before quitting the firing session. I have not seen much, if any changes in groups, once the load is worked up. If at all possible, I test fire the rifle in the area where I am hunting, especially after a flight out or long highway trip. Rifles can get knocked around and if hit hard enough the groups can be affected, but it takes a pretty good hit to disturb the zero.